You should be fine with the current set up but probably not for the long haul as that truck is getting older but like you stated you will upgrade the truck. 2 things of advice I could give is stay at at least 1600lbs of payload and you will be fine and I would recommend the longer wheelbase truck 157" as they tow quite a bit more stable than the 145" wheelbase trucks....ask me how I know I have a 11 3.5 eco with the 145" and a 18 3.5 eco with the 157" wheelbase...both tow my rig great but the 157 does it that much better...